A filing calendar cannot be deleted once in use.


  "code": "FilingCalendarCannotBeDeleted",
  "target": "Unknown",
  "details": [
      "code": "FilingCalendarCannotBeDeleted",
      "number": 900,
      "message": "Unable to delete this filing calendar",
      "description": "There is a current approved worksheet for this filing calendar.  Filing calendars cannot be deleted with an approved worksheet associated with it.",
      "faultCode": "Client",
      "helpLink": "",
      "severity": "Error"


Filing calendars cannot be deleted after they have been used to approve a tax return for filing.

Once a filing calendar has been used, it must be retained for audit purposes.

To stop filing on a filing calendar, please use the expire API.